Tokyo – NHK is conducting research and development on a large-capacity terrestrial transmission technology to realise 8K (Super Hi-Vision) (hereafter referred to as 8K) terrestrial broadcasting. On this occasion, a long-distance test transmission was successfully achieved.

In the test, a compressed 8K signal was transmitted on a single UHF-band channel (6-MHz bandwidth), from a test station at NHK’s Hitoyoshi TV relay station in Hitoyoshi City, Kumamoto Prefecture. It was confirmed that at this time NHK has managed to send the 8K signal to a receiving station 27 km away, the same distance that can be achieved by current terrestrial digital broadcasting.

In order to transmit the 8K signal, whose resolution is 16 times greater than current HDTV signal, it was essential to utilise new technologies that expand transmission capacity, such as ultra-multilevel OFDM (*1), a method of encoding digital data on multiple carrier frequencies that is also used in Wi-Fi, and dual-polarised MIMO (*2), a technique in which multiple antennas are used at the points of transmission and reception to enhance performance, in addition to image data compression technology.

In May 2012, NHK’s Science & Technology Research Laboratories successfully completed the world’s first terrestrial 8K test transmission over a distance of approximately 4.2 km. This test showed that 8K signals can be transmitted over even longer distances, demonstrating that it can be delivered to homes. In order to strive for the speedy realisation of 8K terrestrial broadcasting, NHK plans to push on further with its research and development. NHK is carrying out this test with the support of the Ministry of Internal Affairs and Communications.